Device for the dosed administration of a fluid product, adapted for the replacement of a container

ABSTRACT

A device for administering a fluid product, the device including a first housing part provided with a receiver for the product, a second housing part detachably connectable to the first housing part, a piston rod held such that it can be displaced for the exertion of an emptying movement, an actuatable or releasable drive element for the piston rod, a coupling element including a coupling input element that couples the drive element to the piston rod in a coupling engagement, transmits a driving force of the drive element to the piston rod, and triggers the emptying movement, and a decoupling element displaceably connected to the second housing part and coupled to the first housing part such that it is displaced, by a movement of the housing parts in relation to each other when the housing parts are separated into a decoupling position wherein the piston rod is decoupled from the coupling input element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/178,893 filed Jul. 8, 2011, issued as U.S. Pat. No. 9,057,369 on Jun.16, 2015, which is a continuation of U.S. patent application Ser. No.11/769,496, filed Jun. 27, 2007, issued as U.S. Pat. No. 7,976,494 onJul. 12, 2011, which is a continuation of International ApplicationNumber PCT/CH2005/000710, filed Nov. 30, 2005, which claims priority toGerman Application Number DE 10 2004 063 645.1, filed on Dec. 31, 2004,the contents of all of which are incorporated in their entirety hereinby reference.

BACKGROUND

The present invention relates to devices for delivering, injecting,dispensing, infusing and administering substances, and to methods ofmaking and using such devices. More particularly, it relates to adevices for injecting or administering a medicinal fluid product. Insome embodiments, the device may be an injection apparatus, such as aninjection pen, for self-administering the product.

Injection apparatus or devices are well-known from diabetes therapy,administering growth hormones or osteoporosis preparations. Such devicesshould on one hand guarantee that the correct dosage is administeredand, on the other hand, should be simple and convenient to operate.

An injection apparatus known from WO 97/10865 comprises two casing partswhich are screwed together. A reservoir containing a product to beadministered is accommodated in one of the casing parts, and a conveyingand dosing means is accommodated in the other casing part. The conveyingand dosing means includes a piston which is accommodated in thereservoir, and a piston rod which acts on the piston in an advancingdirection for delivering a settable dosage. The conveying and dosingmeans also includes a drive member which can be operated by a user forsetting the dosage and delivering it. The drive member is coupled to thepiston rod via two spindle drives. The piston rod is linearly guided bythe casing part which accommodates the reservoir. Once the reservoir isempty, the user has to rotate the piston rod back while simultaneouslypressing on the drive member to reuse the apparatus with a filledreservoir.

An injection apparatus comprising a mechanism which is comparable to thecoupling between the piston rod and the drive member is known from WO99/38554.

SUMMARY

It is an object of the present invention to provide a device foradministering a fluid product which allows an empty reservoir to bechanged simply and reliably.

In one embodiment, the present invention comprises a device foradministering a fluid product comprising a first housing part providedwith a receiver for the product, a second housing part detachablyconnectable to the first housing part, a piston rod held such that itcan be displaced for the exertion of an emptying movement, an actuatableor releasable drive element for the piston rod, a coupling elementcomprising a coupling input element that couples the drive element tothe piston rod in a coupling engagement, transmits a driving force ofthe drive element to the piston rod, and triggers the emptying movement,and a decoupling element displaceably connected to the second housingpart and coupled to the first housing part such that it is displaced, bya movement of the housing parts in relation to each other when thehousing parts are separated into a decoupling position wherein thepiston rod is decoupled from the coupling input element.

In one embodiment, the present invention relates to a device foradministering a fluid product, comprising at least two casing partswhich are detachably connected to each other, one of which forms areservoir for the product or a space for receiving for a productcontainer, and the second of which forms a bearer for a conveyingmechanism. In some embodiments, the conveying mechanism comprises aconveying and dosing mechanism or systems, using which a dosage of theproduct to be delivered can be set. The conveying mechanism includes apiston rod which is held by the second casing part, a drive member forthe piston rod which is also held by the second casing part, and acoupler which couples the drive member to the piston rod in a couplerengagement. The drive member is coupled, in some embodiments, purelymechanically to the piston rod such that operating or triggering thedrive member automatically causes a delivery movement of the piston rod,which delivers the product. The product can for example be insulin, agrowth hormone, an osteoporosis preparation or another medicine, or inprinciple even a non-medicine, which can be administered to a human oran animal.

To be able to change the reservoir as simply and quickly as possible,e.g., when it is empty, a decoupling member is provided in accordancewith the invention, for which the second casing part also forms thebearer and which is coupled to the first casing part when the casingparts are connected, e.g., via a mechanical engagement which existsdirectly between the decoupling member and the first casing part. Thecoupling is formed such that a movement of the casing parts relative toeach other, which detaches the casing parts from each other, moves thedecoupling member relative to the second casing part into a decouplingposition in which it decouples the piston rod from the drive member. Thedecoupling member holds the coupler in a retracted state, i.e. couplermembers which are in coupler engagement for delivery are separated fromeach other by the decoupling member and the coupler engagement isprevented or, if necessary, released.

Due to the decoupling, the usually extended piston rod can be reset,i.e. retracted, for a reservoir change, without it acting on the drivemember. If, in accordance with some preferred embodiments, the drivemember is coupled to a dosage display and/or a dosing member, theretracting piston rod does not have a feedback effect on the dosagedisplay and/or the dosing member. Correspondingly, the user does nothave to correct the drive member, a dosage display, dosing member orother component of the device after a reservoir change.

In preferred embodiments in which the device is equipped with the optionof setting a dosage which may be delivered by a delivery process, itscapacity for being set can be configured such that it is set once, forexample by a physician, and the user then self-administers the dosagewhich was set once each time he/she performs a delivery process oroperation.

In some preferred embodiments, the dosage can be individually set foreach delivery process, such that a user who is self-administering theproduct can flexibly set the dosages according to requirement. A devicewhich allows the dosage to be set includes a dosing member which can beformed by the drive member or may be provided in addition to the drivemember and coupled, mechanically or otherwise, to the drive member suchthat a dosing movement of the dosing member results in a dosing movementof the drive member.

In a preferred embodiment, a dosage display for displaying the productdosage set is provided. The display can be an acoustic display and/or atactile display and/or an optical display. The dosage display is coupledto the dosing member, and also to the drive member if the drive memberdoes not already form the dosing member, such that a movement which thedosing member performs when the product dosage is being set causes achange in the product dosage displayed. In the decoupling position, thedecoupling member advantageously decouples the dosage display—and/or thedosing member if one is provided in addition to the drive member—fromthe piston rod in the same way as it decouples the drive member from theconveying member. As applicable, however, the decoupling can also bebrought about at a different point on a coupling between the conveyingmember and the dosing member and/or the conveying member and thedisplay, by holding what is then the other coupler at the relevantinterface in a retracted state.

For setting the dosage, the drive member is decoupled from the conveyingmember even when the casing parts are connected. If the device isadditionally equipped with a dosage display and/or a dosing member, thedosage display and/or the dosing member for setting the dosage may alsobe decoupled from the conveying member when the casing parts areconnected to each other. In another preferred embodiment, a dosagedisplay and/or a dosing member for setting the dosage can be decoupledfrom the conveying member while the drive member is coupled to theconveying member during setting. The decoupling enables the dosage to befreely selected, i.e. the dosage can be increased or reduced, withouthaving a feedback effect on the piston rod.

If the drive member for setting the dosage is decoupled from theconveying member, it is coupled to the conveying member by a couplermovement to cause its delivery movement.

The drive force may be applied manually in one embodiment. In a secondembodiment the force may be supplied by a spring drive, which forms thedrive member in such an embodiment. In other embodiments, the driveforce can also be applied using motors.

If the drive force is applied manually, a path distance of the drivemovement is subdivided into a coupler path portion and an adjoiningdelivery path portion. Once the coupler path portion has been travelled,the drive member is coupled to the conveying member and from then ondrives the conveying member over the delivery path portion. In otherembodiments, in which the drive force is a spring force or a motorforce, the coupler movement is caused by operating a triggering element.As soon as the coupler is relieved of an operating force, motor force orstored force, for example a spring force, to be exerted on the drivemember or a triggering element for delivering, the coupling is releasedautomatically. The drive member, or a coupler member which transfers thedrive movement, is advantageously charged for this purpose with arestoring force acting counter to the coupler movement to automaticallyrelease the coupling between the drive member and the piston rod whenthe drive member is relaxed. Alternatively, it would also be conceivablefor a coupler which is closed for driving the piston rod to be opened,i.e. for the coupler engagement to be released, by the user by manuallymoving the drive member or alternatively another decoupling member.

In a further development of the present invention, the output-side partof the coupler connected to the piston rod is fixed on the second casingpart when the device is in its resting state, such that the piston rodcannot perform a delivery movement, but rather has to be deliberatelyreleased, for example directly connected with delivering the product. Itis advantageous if the fixation on the casing part is released by thecoupler movement. In some preferred embodiments, the coupler engagementis established in a first phase of the coupler path portion of the drivemovement of the drive member, or the coupler movement of a couplermember, and the fixation on the casing is released in a subsequent,second phase, advantageously against the elastic restoring force alreadydescribed. In a preferred embodiment, the coupler includes a couplerintermediate member which on the one hand is in an engagement, whichcauses the fixation on the casing part, with the second casing part, thedecoupling member or another element, and on the other hand is inanother engagement with the piston rod, either directly itself or viaone or more other intermediate member, wherein the coupler intermediatemember is in both engagements when the device is in its resting state,and only in engagement with the piston rod once the coupler engagementhas been established.

In some preferred embodiments, the decoupling member is held movably onthe second casing part and is in a guiding engagement with the firstcasing part or an adaptor structure. For the guiding engagement, eitherthe decoupling member or the first casing part forms a guiding curve,and the other forms an engaging element guided by the guiding curve. Ifan adaptor structure is provided, the same applies to the guidingengagement which is then between the decoupling member and the adaptorstructure. When the two casing parts are detached, the decoupling memberis moved relative to the second casing part by the guiding engagement,out of a resting position into the decoupling position, andautomatically back into the resting position when the casing parts areconnected. The guiding curve is therefore shaped such that in thepositive-lock guiding engagement, the relative movement of the casingparts when they are released is converted into the movement of thedecoupling member relative to the second casing part. Although othermechanisms could also be realized to automatically transfer thedecoupling member to the decoupling position when the casing parts arereleased, for example by a spring force, the embodiment of a guidingengagement enables the path travelled by the decoupling member into thedecoupling position, and therefore the decoupling position relative tothe second casing part, to be comparatively freely configured. Thedecoupling member can be moved into the decoupling position, counter tothe direction in which the first casing part is detached from the secondcasing part. Using a guiding engagement, the decoupling member canadvantageously be securely locked in the decoupling position, and thelocking connection reliably released by connecting the casing parts. Inparticular, detaching the casing parts can move the decoupling memberinto the decoupling position, counter to the direction of the couplermovement which establishes the coupler engagement.

Although the coupler can in principle be formed directly between thedrive member and the piston rod, by forming corresponding engagingelements on the two members which, in the coupler engagement, areconnected to each other in a positive lock, a frictional lock or in apositive and frictional lock, preferred embodiments of the couplerinclude a coupler output member which is coupled to the piston rod.During product delivery, the coupler output member is driven by thedrive member and drives off onto the piston rod. In the decouplingposition, the decoupling member decouples the coupler output member fromthe drive member, while the coupling to the piston rod remains extant.The coupler output member is in direct engagement with the piston rod,said engagement driving the piston rod. The engagement can be a purelypositive lock or a purely non-positive lock. It may be formed as apositive and non-positive lock. In some embodiments, it can be athreaded engagement, wherein the thread pitch in the threaded engagementis large enough that a forced translational movement of the piston rodis possible in the direction of the threaded axis when the coupleroutput member is axially fixed, i.e. the threaded engagement is notself-locking.

The coupler includes a coupler input member which is coupled to thedrive member and is in direct engagement with the drive member. Thecoupling can be a purely positive lock or a purely non-positive lock. Insome embodiments, it may be formed as a positive and non-positive lockand/or as a threaded engagement. The threaded engagement is notself-locking such that in the threaded engagement, the drive member canbe axially moved by a drive force acting on the drive member in thedirection of the threaded axis.

In embodiments in which the coupler input member is driven rotationallyin a first threaded engagement, and the coupler output member drives aconveying member translationally via another, second threaded engagementor is in a second threaded engagement directly with the conveyingmember, the two threaded engagements advantageously form a reducing gearwhich reduces the path distance of the drive movement to a shorter pathdistance of the delivery movement. In some preferred embodiments, thereduction measures at least 2:1 or 3:1.

In a preferred embodiment, the coupling between the dosage display andthe drive member remains extant in the coupler engagement, such that asdelivery progresses, a drive movement of the drive member, counter tothe dosing movement, is progressively reset in the same way. Ifadministering is prematurely aborted, whether deliberately orerroneously and unknowingly, the dosage display thus displays theremainder of the dosage set which has not yet been delivered. This canbe advantageous when the dosage set is larger than what is stillavailable.

If, as in some preferred embodiments, a dosing member is provided inaddition to the drive member, the drive member and the dosing member areadvantageously decoupled from each other in the coupler engagement, suchthat during the drive movement of the drive member no manipulations canbe performed on the dosing member which would have a feedback effect onthe drive member.

In some preferred embodiments in which the drive member drives thecoupler input member rotationally, a spiral spring can form the drivemember. The spiral spring is wound around a rotational axis of therotational movement, wherein at least one outer spring winding surroundsan inner spring winding. The spring exhibits a zero pitch with respectto the rotational axis all over. Using the spiral spring can save onaxial length, as compared to springs in which the windings are arrangedaxially next to each other. One of the two ends of the spiral spring,e.g. its radially inner end, is connected, secured against rotating, tothe coupler input member. The other end, e.g., the radially outer end,is connected, secured against rotating, to the second casing part. Thecoupler input member advantageously forms a reel on which the spiralspring is wound. When setting the dosage, the coupler input member isrotated about the rotational axis, which tenses the spiral spring. Asuitable rotational block, for example a ratchet or the like, ensuresthat the coupler input member can only be rotated in one direction. Therotational block is releasable to be able to correct an incorrectly setdosage. If the rotational block is released, then the worst that canhappen if the device is operated erroneously is that the coupler inputmember is rotated too far back due to the effect of the tensed drivespring. Since the coupler engagement, which couples the coupler inputmember to the piston rod, has not yet been established when the dosageis being set, since the coupler input member is decoupled from thepiston rod, such operational errors cannot affect the piston rod.

In some preferred embodiments in which the coupler includes the couplerinput member and the coupler output member, the decoupling memberdecouples the coupler output member from the coupler input member in thedecoupling position. If the coupler engagement is directly between thesetwo coupler members, the decoupling member holds them in a positionretracted from each other, in the decoupling position. In some preferredembodiments, the coupler additionally includes a coupler intermediatemember which is in engagement with the coupler input member on the inputside and with the coupler output member on the output side and soestablishes the coupler engagement. It is sufficient for decoupling torelease only one of these two engagements of the coupler intermediatemember. Alternatively, the decoupling member releases or prevents bothengagements of the coupler intermediate member, in the decouplingposition. The coupler intermediate member can be the one described inconnection with the resting state.

Although the features and developments described herein set forth aninjection apparatus comprising a coupler in accordance with the presentinvention, an injection device in accordance with the present inventionneed not necessarily comprise the feature of decoupling when changingthe container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an injection apparatus of one exemplary embodiment of thepresent invention, in a perspective view;

FIG. 2 shows, in a longitudinal section, the injection apparatus of FIG.1, including the coupler thereof, with the coupler open;

FIG. 3 shows the injection apparatus of FIG. 1 with the coupler closed;

FIG. 4 is a detail from FIG. 2;

FIG. 5 is a detail from FIG. 3;

FIG. 6 shows the injection apparatus of FIG. 1 after a dosage has beenset;

FIG. 7 shows the injection apparatus of FIG. 1 after a reservoir hasbeen emptied;

FIG. 8 shows a decoupling member and a casing part of the injectionapparatus of FIG. 1;

FIG. 9 shows a distal portion of the injection apparatus of FIG. 1 withthe casing parts connected;

FIG. 10 shows the distal portion while the casing parts are beingdetached;

FIG. 11 shows, in a longitudinal section, another exemplary injectionapparatus, with the coupler open;

FIG. 12 shows the injection apparatus of FIG. 11, with the couplerclosed, in a different longitudinal section;

FIG. 13 shows a detail from FIG. 11;

FIG. 14 shows a detail from FIG. 12;

FIG. 15 shows the injection apparatus of FIG. 11, after a dosage hasbeen set;

FIG. 16 shows the injection apparatus of FIG. 11, after the reservoirhas been emptied;

FIG. 17 shows the injection apparatus of FIG. 11, with the casing partsdetached from each other;

FIG. 18 shows a detail from FIG. 17;

FIG. 19 an injection device of another exemplary embodiment of thepresent invention;

FIG. 20 a proximal part of the injection device of FIG. 19, with thecoupler open;

FIG. 21 the injection device of FIG. 19, with the coupler closed;

FIG. 22 the proximal part of the injection device of FIG. 19, whencorrecting the dosage;

FIG. 23 the proximal part of the injection device of FIG. 19, after thereservoir has been emptied; and

FIG. 24 a blocking member and a stopping member of the injection deviceof FIG. 19.

DETAILED DESCRIPTION

With regard to fastening, mounting, attaching or connecting componentsof the present invention, unless specifically described as otherwise,conventional mechanical fasteners and methods may be used. Otherappropriate fastening or attachment methods include adhesives, weldingand soldering, the latter particularly with regard to the electricalsystem of the device, if any. In embodiments with electrical features orcomponents, suitable electrical components and circuitry, wires,wireless components, chips, boards, microprocessors, inputs, outputs,displays, control components, etc. may be used. Generally, unlessotherwise indicated, the materials for making the present inventionand/or its components may be selected from appropriate materials such asmetal, metallic alloys, ceramics, plastics, etc.

FIG. 1 shows one embodiment of the present invention comprising aninjection apparatus comprising a first casing part 1 and a second casingpart 4 detachably connected to each other. In this exemplary embodiment,the casing parts 1 and 4 are screwed to each other. The injectionapparatus is formed as a slim injection pen. The casing part 1 serves toaccommodate a container 2 filled with a fluid product and in this senseforms a reservoir, and the casing part 4 serves as a bearer for a dosingand drive means, a dosing member 18 of which can be seen. The casingpart 4 is breached in the region of the dosing member 18, such that auser has direct access to the dosing member 18. The dosing member 18 ismounted such that it can be rotated about a central longitudinal axis ofthe apparatus, and formed as a sleeve which is ribbed on its outercircumference so as to be user-friendly. A dosage display 20 can also beseen, which is laterally placed through a breach in the shell of thecasing part 4.

FIG. 2 shows the injection apparatus of the first exemplary embodiment,in a longitudinal section. The container 2 is accommodated in the casingpart 1. In the container 2, a piston 3 is accommodated such that it canbe moved in an advancing direction V. The piston 3 seals the container2, fluid-proof, at its proximal end. Advancing the piston 3 in theadvancing direction V displaces and delivers product through an outletof the container 2, e.g., through an injection needle protruding intothe outlet and fastened to the distal end of the casing part 1 by aneedle holder. The container 2 may be formed in the manner ofconventional ampoules. The casing part 1 directly forms a container orampoule holder. The proximal end of the casing part 1 protrudes into thecasing part 4 and is screwed to the casing part 4.

The casing part 4 accommodates a piston rod 15 and other componentscomprising a dosing and drive means or mechanism. In a dosing and driveline, the dosing and drive means includes a drive member 5 and a couplerwhich in a coupled state, i.e. in a coupler engagement, couples thedrive member 5 to the piston rod 15. The piston rod 15, together withthe piston 3, comprises a conveying means. In the coupled state, couplermembers 6-10 transfer a drive force exerted on the drive member 5 ontothe piston rod 15. No coupler engagement exists in FIG. 2, such that thepiston rod 15 is decoupled from the drive member 5. In this decoupledstate, the user can set the product dosage to be administered, by adosing movement of the dosing member 18, e.g., a rotational movement.

The drive member 5 is sleeve-shaped. On its shell outer area, itcomprises a thread about a threaded axis R pointing in the advancingdirection V. Via this thread, the drive member 5 is in threadedengagement with a coupler input member 6. The coupler input member 6 isalso sleeve-shaped and provided with a corresponding inner thread forthe threaded engagement. The thread pitch in the threaded engagement islarge enough that self-locking cannot occur. The dosing member 18surrounds the coupler input member 6 and is connected to the couplerinput member 6 such that it is secured against rotating and cannot bemoved axially. The piston rod 15 protrudes into the drive member 5 andthe coupler input member 6.

The piston rod 15 is provided with an outer thread over its axiallength. Via the outer thread, it is in threaded engagement with acoupler output member 9 which is provided with a corresponding innerthread. These two threads also exhibit a thread pitch which preventsself-locking in the threaded engagement. The thread pitch is less thanthe thread pitch in the threaded engagement between the drive member 5and the coupler input member 6. A coupler sleeve 8 is connected to thecoupler output member 9 such that it is secured against rotating andcannot be moved axially. The coupler sleeve 8 and the coupler outputmember 9 can be regarded as an integral component with respect to themovements between the drive member 5 and the piston rod 15. They may beembodied in two parts and fixedly connected to each other. The coupleroutput member 9 and the coupler sleeve 8 are mounted in the casing part4 such that they can be rotated about the threaded axis R of the coupleroutput member 9 but cannot be moved axially. In the threaded engagement,the piston rod 15 protrudes through the coupler output member 9 andprotrudes into the coupler sleeve 8. The equalizing spring 17 is clampedbetween a proximal end of the coupler sleeve 8 and a proximal end of thepiston rod 15 and acts on the piston rod 15 in the advancing direction Vas a pressure spring. The equalizing spring 17 presses onto the pistonrod 15 via a disc 15 a which is supported such that it can be rotated onthe piston rod 15 and forms a flange of a sleeve placed onto the pistonrod 15.

The piston rod 15 is linearly guided in and counter to the advancingdirection V in a linear guide 4 a, such that it cannot be rotatedrelative to the casing part 1. The drive member 5 is also linearlyguided relative to the casing part 4 such that it can be moved in andcounter to the advancing direction V, for which purpose the casing part4 directly forms a linear guide 4 b.

The threaded axis of the piston rod 15 forms a main movement axis of thedevice. It forms a rotational axis R for the rotational drive movementof the coupler input member 6 and, via the coupler intermediate member7, the coupler output member 9. It forms both threaded axes. It alsoforms the translational axis for the piston rod 15 and the drive member5.

The coupler also includes a coupler intermediate member 7 and arestoring member 10 which is formed as a pressure spring and charges thecoupler intermediate member 7 with an elasticity force acting counter tothe advancing direction V. The restoring member 10 is clamped betweenthe coupler output member 9 and the coupler intermediate member 7.

If no force acting in the advancing direction V is exerted on the drivemember 5, the restoring member 10 ensures, via the coupler intermediatemember 7, that the coupler engagement is released. This state is shownin FIG. 2. The coupler input member 6 is pressed in the advancingdirection V until it abuts against the coupler intermediate member 7,and is pressed into a proximal end position by the restoring member 10via the coupler intermediate member 7. By using the coupler intermediatemember, the restoring member 10 holds the coupler input member 6 in aholding position relative to the coupler output member 9 and the couplersleeve 8 fastened to it. The restoring member 10 and the couplerintermediate member 7 thus form a holding means, acting in anon-positive lock, for the coupler input member 6.

FIG. 3 shows the injection apparatus in a coupled state. A couplerengagement exists between the coupler input member 6 and the couplersleeve 8. For the coupler engagement, the coupler input member 6 and thecoupler sleeve 8 form engaging elements which, in the couplerengagement, establish a rotationally secured connection between the twomembers 6 and 8 about the threaded axis R pointing in the advancingdirection V. The engaging elements co-operate as grooves and springs orteeth which are formed parallel to the advancing direction V and evenlydistributed about the threaded axis R.

FIGS. 4 and 5 show the region of the coupler engagement in detail. FIG.4 shows the apparatus in the decoupled state and FIG. 5 shows theapparatus in the coupled state. FIG. 4 thus corresponds to FIG. 2, andFIG. 5 thus corresponds to FIG. 3.

In the decoupled state, the coupler input member 6 is retracted from thecoupler sleeve 8 counter to the advancing direction V, such that thecoupler input member 6 can be freely rotated relative to the couplersleeve 8 and therefore the coupler output member 9 fixedly connected toit. The coupler output member 9 is simultaneously connected, such thatit cannot be rotated, to the casing part 4 via the coupler sleeve 8, thecoupler intermediate member 7 and a decoupling member 11. For thisrotationally secure coupling, the coupler intermediate member 7 isprovided with engaging elements 7 b on an inner area radially facing thecoupler sleeve 8, and the coupler sleeve 8 is provided withcorresponding engaging elements 8 b. For the rotationally securedengagement with the decoupling member 11, the coupler intermediatemember 7 is provided with engaging elements 7 a on an outercircumferential area, and the decoupling member 11 is provided withradially facing engaging elements 11 a on a shell inner area which, inthe decoupled state, interlock with each other—like the engagingelements 7 b and 8 b—in the manner of grooves and springs or teethparallel to the advancing direction V. The coupler intermediate member7, in its rotationally secured engagement with the coupler sleeve 8 andits rotationally secured engagement with the decoupling member 11, canbe moved axially in and counter to the advancing direction V, whereinthe engagement with the decoupling member 11 is released when it movesin the advancing direction V.

If the drive member 5 is operated by exerting a pressure force on atriggering element 16 in the advancing direction V, the drive member 5and the coupler input member 6 together complete an axial coupler strokeof length X. In this drive stroke movement or coupler movement, thecoupler input member 6 pushes the coupler intermediate member 7 in theadvancing direction V, against the restoring elasticity force of therestoring member 10. In the course of the stroke movement, the engagingelements 6 a and 8 a pass into engagement with each other, while thecoupler intermediate member 7 simultaneously moves relative to thedecoupling member 11 until it passes out of the rotationally securedengagement with the decoupling member 11. The coupler intermediatemember 7 remains in the rotationally secured engagement with the couplersleeve 8. The coupler movement is limited by a stopper of the triggeringelement 16 on the coupler sleeve 8; in the exemplary embodiment, on itsproximal facing area (FIG. 3).

FIG. 5 shows the injection apparatus in the coupled state. The engagingelements 6 a and 8 a are axially superimposed, such that the couplerengagement is established as a rotationally secured engagement betweenthe coupler input member 6 and the coupler sleeve 8. The engagementbetween the coupler intermediate member 7 and the decoupling member 11is not released until the coupler engagement is securely established.

For setting the dosage, a user rotates the dosing member 18, which locksin easily releasable locking positions. The dosing member 18 isconnected to the coupler input member 6 such that it is secured againstrotating and also cannot be moved axially, such that the latter rotateswith it. The drive member 5 guided linearly in and counter to theadvancing direction V at 4 b is moved, by the dosing movement of thecoupler input member 6, in the proximal direction and then protrudes outof the casing part 4. The axial dosing path of the drive member 5follows from the rotational angle by which the dosing member 18 isrotated and the thread pitch in the threaded engagement between thedrive member 5 and the coupler input member 6 which abuts against thecoupler intermediate member 7 in the advancing direction V and againstthe casing part 4 counter to the advancing direction V.

FIG. 6 shows the injection apparatus with the container 2 stillcompletely filled, after a first dosage has been set or selected. Inthis state, the user penetrates the skin with the injection needle, fora subcutaneous injection. Once the injection needle has been placed, theuser operates the drive member 5 by pressing it in the advancingdirection V, into the casing part 4. In the first portion of the drivemovement, coupler movement or coupler stroke X, the drive member 5slaves the coupler input member 6, against the elastic restoring forceof the restoring member 10, until the coupler engagement with thecoupler sleeve 8 is established and the rotationally secured engagementbetween the coupler intermediate member 7 and the decoupling member 11is released. As soon as the coupler sleeve 8 and together with it thecoupler output member 9 can freely rotate about the common threaded axisR, the coupler stroke X is complete and a delivery stroke follows as thesecond portion of the drive movement. During the delivery stroke, thedrive member 5 is pressed further in the advancing direction V. Sincethe coupler input member 6 cannot perform any further movement in theadvancing direction V once it abuts axially against the couplerintermediate member 7, it rotates—in the threaded engagement with thedrive member 5 which is guided such that it is secured againstrotating—about the common threaded axis R. When rotated in the couplerengagement, the coupler input member 6 slaves the coupler sleeve 8,which slaves the coupler output member 9. The coupler sleeve 8 is heldin the casing part 4, together with the coupler output member 9, suchthat it cannot be moved axially. The rotational movement of the coupleroutput member 9 advances the piston rod 15, via the threaded engagementwith the piston rod 15 and its rotationally secured linear guide at 4 a,and thus causes the delivery movement of the piston rod 15 and togetherwith it the piston 3. As soon as the injection button 16 passes intoabutting contact against the coupler sleeve 8 in the course of the driveand delivery movement (FIG. 3), the delivery process is complete.

If the user takes the pressure off the triggering element 16, then therestoring member 10 moves the coupler input member 6, via the couplerintermediate member 7, back to the holding position retracted out of thecoupler engagement, as shown in FIGS. 2 and 4. The coupler input member6 and together with it the drive member 5, the dosing member 18 and thedosage display 20, are decoupled from the coupler output member 9 andthus from the piston rod 15 by the retracting movement of the couplerinput member 6. On the other hand, the piston rod 15 is again connectedto the casing part 4, such that it is secured against rotating, via thereturning coupler intermediate member 7 and decoupling member 11.

FIG. 7 shows the injection apparatus at the end of a final deliverywhich has emptied the container 2.

For exchanging the emptied container 2, the casing part 1 is detachedfrom the casing part 4, e.g., by a unscrewing movement. When the casingparts 1 and 4 are detached, the decoupling member 11 is automaticallymoved relative to the casing part 4, counter to the direction of thecoupler movement of the coupler input member 6 and counter to theadvancing direction V. The casing part 4 mounts or carries thedecoupling member 11 accordingly. The axial path which the decouplingmember 11 thus travels relative to the casing part 4 is as long as thecoupler stroke X, such that once the casing parts 1 and 4 have beendetached, the decoupling member 11 lying axially opposite the couplerinput member 6 blocks it, and the coupler input member 6 can no longerbe moved in the advancing direction V, at least not into the couplerengagement with the coupler sleeve 8. Blocking the coupler input member6 in the disengaged position prevents the coupler output member 9 frombeing able to pass into a rotationally secured connection with thecasing part 4 and so prevent the piston rod 15 from retracting. In otherwords, it ensures that the piston rod 15 can be retracted into thecasing part 4, without being blocked.

FIG. 8 shows the decoupling member 11 and the first casing part 1 in aperspective view. The decoupling member 11 is a sleeve part andcomprises, in a distal portion, three engaging elements 12 protrudingradially inwardly and, in a proximal portion, a fixing element 13protruding radially outwardly.

FIG. 9 shows the casing part 1 and a connecting portion of the casingpart 4, wherein the hidden decoupling member 11 is shown by a brokenline. For its decoupling function, the decoupling member 11 isaccommodated in the connecting portion of the casing part 4 such that itcan be rotated and moved axially. Its relative mobility is determined byan axial guide 4 e and a circumferential guide 4 c, along which thefixing element 13 moves in succession when the casing part 1 is detachedfrom the casing part 4. The circumferential guide 4 c extends at a rightangle to the axial guide 4 e, in the circumferential direction about thescrew axis. It is formed as a breach or cavity in the casing part 4.

The decoupling member 11 is in a guiding engagement with the casing part1. For the guiding engagement, one guiding curve 1 a per engagingelement 12 is formed on a shell outer area of the casing part 1 andguides the engaging element 12 and, thus, the decoupling member 11 whenthe casing parts 1 and 4 are detached. Another guiding curve 1 a, spacedin parallel, guides the decoupling member 11 accordingly, when thecasing parts 1 and 4 are connected (FIG. 10). In a distal portion, theguiding curve 1 a runs obliquely, i.e. at a pitch, with respect to thescrew axis of the screw connection between the casing parts 1 and 4,such that in the relative rotation between the casing parts 1 and 4required for detaching them, the engaging element 12 performs an axialmovement of the decoupling member 11 relative to the casing part 4counter to the advancing direction V, sliding along the guiding curve 1a, until the fixing element 13 reaches the axial height of thecircumferential guide 4 c. The pitch measures about 45° and is constant.In principle, it can be selected from the entire range larger than 0°and smaller than 180° and, as applicable, can also be variable, as longas the relative movement required for detaching the casing parts 1 and 4causes a movement of the decoupling member counter to the couplermovement X to be performed by the coupler input member for coupling.

A distal portion of the guiding curve 1 a runs axially, such that whenthe casing parts 1 and 4 are screwed further apart, the fixing element13 is moved along the circumferential guide 4 c. In the course of thisrelative circumferential movement between the decoupling member 11 andthe casing part 4, the fixing element 13 slides over a fixing element 4d in the region of the circumferential guide 4 c. The fixing element 4 dis formed as a cam on a strip portion of the casing part 4. The stripportion acts as a spiral spring which is fixedly clamped on both sidesand elastically gives when the fixing element 13 moves over the fixingelement 4 d, to then spring back again into its initial position andform a releasable locking engagement for the decoupling member 11. Inthe locking position, the fixing element 13 abuts the fixing element 4 din one circumferential direction and in the other circumferentialdirection abuts a collar formed in the circumferential guide 4 c and isthus fixed in both circumferential directions.

FIG. 10 shows the two casing parts 1 and 4 and the decoupling member 11,after its fixing element 13 has been moved behind the fixing element 4 dof the casing part 4. The decoupling member 11 is in the releasablelocking engagement with the casing part 4 via the fixing elements 4 dand 13 and in this way is axially fixed on the casing part 4 such thatit is secured against rotating. In the locking position shown in FIG.10, the decoupling member 11 blocks the coupler input member 6 and thusensures that the drive member 5 and the piston rod 15 are decoupled. Assoon as the decoupling member 11 has reached the locking position, itsengaging element 12 moves out of the guiding engagement with the guidingcurve 1 a when the casing parts 1 and 4 are screwed further apart. Theguiding curve 1 a is shaped accordingly.

When the casing parts 1 and 4 are screwed together again, they arecentred with respect to the circumferential direction by co-operatingcentering elements, such that the engaging element 12 of the decouplingmember 11 passes into engagement with the guiding curve 1 a again. Assoon as the guiding engagement has been established, further screwingtogether automatically moves the decoupling member 11 out of the lockingengagement of the fixing elements 4 d and 13 until it again assumes thesame position relative to the casing part 4 as in FIG. 9 and FIGS. 2 to7. This corresponds to the operational position of the decoupling member11.

While or before screwing together, the piston rod 15 is simply retractedinto the casing part 4, which—due to the released coupler engagement,causes a rotational movement of the coupler output member 9.

The dosage display 20 of the first exemplary embodiment is coupled tothe drive member 5 via a display coupling member 21 and the couplerinput member 6. The display coupling member 21 is connected to thecoupler input member 6 such that it is secured against rotating, bybeing able to move on the coupler member 6 relative to it in and counterto the direction of the coupler movement X, forming a ring in theexemplary embodiment. Conversely, the display coupling member 21 can berotated with respect to the casing part 4 about the rotational axis R,but is held such that it cannot be moved axially relative to the casingpart 4. The display coupling member 21 circumferentially comprisesteeth, which in the exemplary embodiment are conical, via which it is intoothed engagement with a gear of the dosage display 20 to introduce thedosing movement and also the drive movement into the gear.

FIGS. 11-18 show an injection apparatus of another exemplary embodimentof the present invention. The injection apparatus exhibits somemodifications with regard to the coupling and decoupling of the drivemember 5 and piston rod 15. The drive member 5 and the piston rod 15themselves, and how they co-operate in principle when coupling anddecoupling, may remain the same. Functionally identical components areprovided with the same reference numbers as in the first exemplaryembodiment, and, to indicate modifications the relevant components areprovided with the same reference numbers, but apostrophised.

FIG. 11 shows the injection apparatus in its resting state, in which thedrive member 5 is decoupled from the piston rod 15. The first casingpart 1 is covered by a protective cap 37 which is connected to thecasing part 4 and removed for administering the product. Unlike thefirst embodiment, the coupler engagement is established and releasedbetween the modified coupler input member 6′ and the modified couplerintermediate member 7′.

FIG. 12 shows the injection apparatus of the second embodiment in itscoupled state, which is established by charging the triggering element16, and therefore the drive member 5 and the coupler input member 6′,with a drive force acting in the advancing direction V. However, as incorresponding FIG. 3 of the first embodiment above, no dosage has yetbeen selected or only a small dosage of a few units for priming. Theprotective cap 37 has been replaced by a casing part 38 which is placedonto the casing part 4 and snapped onto it. The casing part 38 mounts orcarries a needle protection 39, e.g., in the form of a needle protectingsleeve, such that it can be elastically moved counter to the advancingdirection V. When the injection needle (not shown) is injected, theneedle protection 39 springs counter to the advancing direction V, intothe casing part 38. In a reversal of this movement, the needlepenetrates through a distal opening of the needle protection 39.

FIGS. 13 and 14 show the region of the coupler engagement in detail,wherein FIG. 13 shows for the decoupled state and FIG. 14 shows for thecoupled state. Unlike the first embodiment, the engaging elements 6 aand 7 c between which the coupler engagement is established exhibit aninclination with respect to the advancing direction V. The engagingelements 6 a and 7 c are each formed in the manner of a conical toothedring encircling the threaded axis of the piston rod 15, wherein thecoupler input member 6′ forms its engaging elements 6 a on its distalend as an inner cone, and the coupler intermediate member 7′ forms theengaging elements 7 c on its proximal end as an outer cone. The conicalengaging areas are congruent to each other and lie directly oppositeeach other, axially facing, with the clear distance X. Instead of beingconical, the coupler areas could also be otherwise suitably shaped,e.g., congruently convex/concave.

The coupler intermediate member 7′ can be moved axially and is inengagement with the coupler output member 9, such that it is securedagainst rotating, in any axial position. It is again formed as a sleevepart and mounted on the coupler output member 9 such that it can be slidaxially. For this purpose, it penetrates through the coupler sleeve 8′which is axially slit accordingly, which however is not visible in thefigures. The rotationally secured connection is created in a positivelock via engaging elements formed as axially linear teeth. The restoringmember 10′, which is the same in its embodiment and installation butreduced with regard to its function, is tensed between the coupleroutput member 9 and the coupler intermediate member 7′, as in the firstembodiment, and charges the latter with an elasticity force, counter tothe advancing direction V.

In the decoupled state, in which the coupler input member 6′ isretracted from the coupler intermediate member 7′ counter to theadvancing direction V, as shown in FIG. 13, the restoring member 10′presses the coupler intermediate member 7′ into the rotationally securedengagement with the decoupling member 11′. The corresponding engagingelements are again indicated as 7 a and 11 a. The engaging elements 7 aand 11 a are also formed as conical toothed rings. The engagementbetween the coupler intermediate member 7′ and the decoupling member 11′can alternatively be in a purely frictional lock. In this case, theengaging elements 7 a and 11 a comprise mutually facing congruentfrictional areas which could be mutually facing conical areas.

Another modification exists in the dosing member 18′. Unlike the dosingmember 18 of the first embodiment, the dosing member 18′ cannot be movedrelative to the casing part 4 in the direction of the coupler movementX. Instead, the coupler input member 6′ is again connected to the dosingmember 18′ such that it is secured against rotating, but such that itcan be moved axially. The rotationally secured engagement between thecoupler input member 6′ and the dosing member 18′ exists in thedecoupled state of the drive member 5 and the piston rod 15 and isreleased in the course of the coupler stroke X, namely directly beforethe rotationally secured connection between the coupler output member 9and the casing part 4 is released. For this engagement, the couplerinput member 6′ and the dosing member 18′ are provided with engagingelements 6 b and 18 a which are formed on shell areas, radially facingeach other, of the two members 6′ and 18′ in the manner of grooves andsprings. With respect to the rotationally secured connection between thecoupler input member 6′ and the dosing member 18′, reference may also bemade to FIGS. 11 and 12. The rotationally secured connection exists inthe decoupled state shown in FIG. 11, and is released in the coupledstate shown in FIG. 12.

Another difference with respect to the first embodiment exists withregard to the holding means. In the second embodiment, the restoringmember 10′ has no effect which separates the coupler members 6′ and 9from each other. The holding means of the second embodiment includes arestoring member 14, a supporting structure 6 c and the dosing member18′. The restoring member 14 charges the coupler input member 6′, viathe supporting structure 6 c, with an elastic restoring force whichcounteracts the coupler movement X of the coupler input member 6′. Inthe direction of the coupler movement X, which coincides with theadvancing direction V, the restoring member 14 is supported on thedosing member 18′ which forms a supporting collar for this purpose. Thesupporting structure 6 c is connected to the coupler input member 6′such that it cannot be moved in or counter to the direction of thecoupler movement X. It is formed as a short sleeve with an outer flangeon which the restoring member 14 is supported. Counter to the directionof the coupler movement X, the supporting structure 6 c abuts withrespect to the casing part 4. The coupler movement X moves the couplerinput member 6′, against the elastic restoring force of the restoringmember 14, into the coupler engagement with the coupler intermediatemember 7′. As in the first embodiment, the restoring member 14 is formedas a pressure spring charged with a pressure force in the direction ofthe coupler movement X.

The mode of operation of the modified coupler (comprising components6′-11′ and 14′) is the same as the coupler of the first embodiment.Thus, in the decoupled state, the coupler output member 9 is connected,such that it is secured against rotating, to the casing part 4 via thecoupler sleeve 8′, the coupler intermediate member 7′ and the decouplingmember 11′. Operating the injection button 16 and consequentlyperforming the coupler stroke X (FIG. 11) establishes the couplerengagement, in the second embodiment between the coupler input member 6′and the coupler intermediate member 7′. In the first phase of thecoupler stroke X, the engaging elements 6 a and 7 c interlock with eachother, such that the coupler input member 6′ is connected, such that itis secured against rotating, to the coupler output member 9 via thecoupler intermediate member 7′ and the coupler sleeve 8′. Only once therotationally secured engagement has been established is the couplerintermediate member 7′ moved out of engagement with the decouplingmember 11′ by the coupler input member 6′ pressing in the advancingdirection V, such that the coupler output member 9 can freely rotateabout the threaded axis R formed with the piston rod 15 and the couplerengagement is completely established.

FIG. 14 shows the injection apparatus in its coupled state, i.e. in thecoupler engagement. FIGS. 15 and 16 correspond to FIGS. 6 and 7 of thefirst exemplary embodiment, such that cross-reference can be made.

FIG. 17 shows the injection apparatus of the second embodiment while thereservoir 2 is being exchanged. Once the reservoir 2 has been emptied,as shown in FIG. 16, the casing part 1 is detached from the casing part4, which moves the decoupling member 11′ into the decoupling position.This function fully corresponds to that of the decoupling member 11 ofthe first embodiment, such that reference can be made to theexplanations in that embodiment and to FIGS. 8-10.

In the state shown in FIG. 17, the casing part 1 is alreadyaccommodating the new reservoir 2. To connect the casing part 1 to thecasing part 4, the casing part 1 can be moved towards the casing part 4using the piston 3 which proximally seals the reservoir 2. The pistonrod 15 which freely protrudes out of the casing part 4 is moved back bythe pressing piston 3 in the threaded engagement with the coupler outputmember 9 which can be freely rotated but is axially fixed. Due to therotationally secured linear guide 4 a, which in the second embodiment isformed by a coupler receptacle which is inserted into the casing part 4such that it is secured against rotating, the piston rod 15 completes anaxial linear movement when retracted, while the coupler output member 9freely rotates, together with the coupler sleeve 8′, about the commonthreaded axis. Instead of moving the piston rod 15 back, pressingagainst the piston 3, the piston rod 15 can also be moved backbeforehand by pressing directly on its plunger.

FIG. 18 shows the coupler region, with the decoupling member 11′situated in the decoupling position, in detail. The function of thedecoupling member 11′ corresponds to that of the first embodiment,namely blocking the coupler input member 6′ in the retracted axialposition.

The dosing movement and the drive movement are also introduced into agear of the dosage display 20′ via the coupler input member 6′ and adisplay coupling member 22 in the second embodiment. The displaycoupling member 22 is also connected to the coupler input member 6′,such that it is secured against rotating, and cannot be moved relativeto the casing part 4 in and counter to the direction of the couplermovement X.

FIGS. 19-24 show another exemplary embodiment of an injection apparatusin accordance with the present invention in which, during administering,the drive force for delivering the product is not applied manually butrather by a drive member 25 formed as a drive spring. The drive member25 is tensed by setting the dosage to be administered. The spring energyabsorbed when setting the dosage is released when the apparatus istriggered and converted into advancing the piston rod 15.

FIG. 19 shows the injection apparatus with the assembled casing part 38and the needle protection 39 accommodated in it such that it can be slidcounter to the advancing direction V, against the force of a restoringspring.

FIGS. 20 and 21 show the casing part 4 with the operational and othercomponents of the injection apparatus accommodated in it. In FIG. 20 itis in a resting state, comparable to the preceding embodiments, in whichthe dosage can be set and, in FIG. 21, it is in the coupler engagement.Unless stated differently below, reference is made in particular toFIGS. 20 and 21.

The drive member 25 is a spiral spring acting as a torsion spring,comprising spring windings which encircle the threaded axis R of thethreaded engagement between the coupler output member 9 and the pistonrod 15. The spring windings are arranged one over the other, radiallywith respect to the threaded axis R; they exhibit a zero pitch withrespect to the threaded axis. An inner end of the spring windings isfastened to the coupler input member 6′, and an outer end is fastened toa supporting structure 26 which is connected to the casing part 4 suchthat it can be moved in the direction of the coupler movement X but issecured against rotating. On the other hand, the supporting structure 26is connected to the coupler input member 6′ such that it cannot be movedin and counter to the direction of the coupler movement X. The couplerinput member 6′ can be rotated about the threaded axis R relative to thesupporting structure 26. Another supporting structure 6 d is connectedto the coupler input member 6′ such that it cannot be moved in andcounter to the direction of the coupler movement X. The coupler inputmember 6′ and the supporting structure 6 d may be formed integrally. Thedrive member 25 is axially enclosed by the supporting structures 6 d and26.

The functionality of the coupler corresponds generally to that of thesecond embodiment, such that the same reference signs are used for thecoupler members 6′-10′ and the decoupling member 11′. Unlike the couplerof the second embodiment, however, the coupler sleeve 8′ in thatembodiment has been omitted. The coupler intermediate member 7′ isdirectly in an engagement with the coupler output member 9 whichtransfers the rotational drive movement of the coupler input member 6′onto the coupler output member 9.

A dosage display 20″ is coupled to the coupler input member 6′ via adisplay coupling member 23. Like the display coupling members 21 and 22of the other embodiments above, the display 20″ is connected to thecoupler input member 6′, such that it is secured against rotating. Thedisplay coupling member 23 cannot be moved in and counter to thedirection of the coupler movement X relative to the casing part 4. As inthe first and second embodiments described above, the rotationallysecured connection of the display coupling member 23 exists both in thedecoupled and in the coupled state of the device.

For setting the dosage and during storage, to prevent the coupler inputmember 6′ from the rotational drive movement and to hold the drivemember 25 in its tensed state, a rotational block or lock is formedbetween the coupler casing 6′ and the casing part 4. In the holdingposition of the coupler members 6′, 7′ and 9 shown, the rotational blockexists between a first blocking member 24 and a second blocking member34. The blocking member 24 is connected to the coupler input member 6′,such that it is secured against rotating. The blocking member 34 isconnected to the casing part 4, such that it is secured against rotatingbut can be moved in and counter to the direction of the coupler movementX relative to the casing part 4 and the coupler input member 6′. Thefacing areas of the blocking members 24 and 34, which contact each otherin the blocking engagement, form a ratchet which allows a rotationalmovement of the coupler input member 6′ which tenses the drive member25, and prevents a rotational movement in the opposite direction.

FIG. 24 shows the coupler input member 6′ together with the blockingmember 24 mounted on it, such that it is secured against rotating, thedisplay coupling member 23 connected to the coupler input member 6′,such that it is secured against rotating, and a connecting part 33connected to the input member 6′ such that it cannot be moved. Thedisplay coupling member 23 forms a units counting ring of the dosagedisplay 20″ and is suitably coupled to a tens counting ring to displaythe dosage set. On a proximal facing side facing the blocking member 34,the blocking member 24 is provided with blocking teeth 24 a which arearranged evenly about the axis R and, in the blocking engagement,co-operate with counter teeth of the blocking member 34, to form therotational block with respect to the drive movement. For a secondfunction connected with dosing and delivery, a shell outer area of theblocking member 24 is provided with a thread 24 b, the threaded axis ofwhich coincides with the threaded axis R of the piston rod 15. Astopping member 27 engages with the thread 24 b. The stopping member 27is guided such that it can be linearly moved parallel to the threadedaxis R, in the exemplary embodiment, in an axial groove on the innershell area of the casing part 4. The blocking member 24 forms arotational stopper 24 c for the stopping member 27, which limits thedrive movement of the coupler input member 6′ which advances the pistonrod 15. It forms another rotational stopper 24 d for the stopping member27, which determines the maximum dosage which can be delivered and set.Another stopping member 27 is arranged on the other side of the threadedaxis R, opposite the stopping member 27 which can be seen in the view inFIG. 23, and co-operates in the same way with two other rotationalstoppers 24 c and 24 d. The thread 24 d is double-threaded. The stoppingmembers 27 simultaneously abut against the respectively assignedrotational stoppers 24 c and 24 d, as can be seen in the cross-sectionalrepresentation in FIG. 23 for the rotational stoppers 24 c. Therotational stoppers 24 c determine a zero dosage position and therotational stoppers 24 d determine a maximum dosage position.

In the third embodiment, the holding means is formed in another variant.It includes a restoring member 19, as well as the display couplingmember 23 and the blocking member 24. The restoring member 19 issupported on the casing part 4 via the display coupling member 23 in thedirection of the coupler movement X and on the blocking member 24counter to the direction of the coupler movement X. The restoring member19 presses the blocking member 24 until it abuts against the connectingpart 33. Since the connecting part 33 is connected to the coupler inputmember 6′ such that it cannot be moved in and counter to the directionof the coupler movement X, the restoring member 19 thus exerts anelastic restoring force, acting counter to the direction of the couplermovement X, on the coupler input member 6′ via the blocking member 24and the connecting part 33, said elastic restoring force holding thecoupler input member 6′ in the holding position retracted out of thecoupler engagement. It again acts as a pressure spring. The blockingmember 24 is a sleeve part comprising an outer shell forming the thread24 b, an inner shell serving to mount it on the coupler input member 6′such that it is secured against rotating, and a base which connects thetwo shells and on which the blocking teeth 24 a are formed. Therestoring member 19 protrudes into the blocking member 24 which iscup-shaped in this way, and is supported on the base of the blockingmember 24.

The restoring member 19 presses the blocking member 24 not only until itabuts against the connecting part 33, but also until it abuts againstthe casing part 4. Abutting in this other way prevents the blockingmember 24 from being able to move counter to the direction of thecoupler movement X beyond the holding position assumed in FIG. 20. Theblocking member 24 can thus be moved relative to the coupler inputmember 6′, against the restoring elasticity force of the restoringmember 19, in the direction of the coupler movement X. Conversely, thecoupler input member 6′ can be moved counter to the direction of thecoupler movement X relative to the blocking member 24 abutting againstthe casing part 4.

The equalizing spring 17, tensed between the piston rod 15 and theconnecting part 33, supports the restoring member 19 in its function ofholding the coupler input member 6′ in the holding position. Theequalizing spring 17 could in principle replace the restoring member 19for retracting the coupler members 6′, 7′ and 9. It is weak enough that,at least once it has been partially relaxed, it can no longer hold thecoupler members 6′-9 in the holding position, and thus can no longerhold the coupler in the decoupled state, with certainty.

A triggering element 28 is provided for triggering the drive member 25.The triggering element 28 can be moved translationally relative to thecasing part 4 in the direction of the coupler movement X—in thisembodiment, the advancing direction V and/or distal direction—androtationally about the rotational axis R of the coupler input member 6′,which coincides with the threaded axis R of the piston rod 15, and isguided in these two movements by the casing part 4. The translationalmovement in the distal direction establishes the coupler engagementbetween the coupler input member 6′ and the coupler intermediate member7′ and releases the rotational block between the blocking members 24 and34, which triggers the drive member 25, i.e. delivery. The translationalmovement in the advancing direction V is therefore also referred to inthe following as the triggering movement.

In another function, the triggering element 28 forms the dosing memberof the third embodiment. Via multiple intermediate members, therotational movement of the triggering element 28 relative to the casingpart 4 sets the product dosage which can be delivered by the nextdelivery process. This movement is also referred to in the following asthe dosing movement. From the zero dosage position, which is shown inFIG. 20 and determined by the stopping members 27 abutting therotational stoppers 29 c of the blocking member 24 which limit the drivemovement of the coupler input member 6′, the dosage can be set byrotating the triggering element 28 in the direction of the rotationaldirection arrow indicated, the dosing direction. The rotational dosingmovement of the triggering element 28 is transferred onto the couplerinput member 6′ via an inner part 29—which is connected to thetriggering element 28 such that it is secured against rotating andshifting or is formed integrally with it—and the connecting part 33. Fortransferring, the inner part 29 and the connecting part 33 are in anengagement with each other, such that they are secured against rotating,and the connecting part 33 is connected to the coupler input member 6′,such that it is secured against rotating. For securing against rotating,the inner part 29 and the connecting part 33 are provided with an innerteeth 29 a and an outer teeth 33 a which interlock with each other inthe resting state of the apparatus and can be axially shifted withrespect to each other.

The triggering element 28 is arranged in the proximal end region of thecasing part 4 so as to be user-friendly. Its outer sleeve part surroundsthe casing part 4. A base of the triggering element 28 forms a proximalend of the injection apparatus. For setting the dosage, the triggeringelement 28 can be operated as a turning button and is ribbed on itsouter shell area for this purpose. For triggering, it can be operated asa push button. During the dosing movement, the triggering element 28locks with the casing part 4 in discrete rotational angular positionscorresponding to the dosage units.

A stopper element 29 b facing a proximal facing area of the connectingpart 33 projects radially inwards from the inner part 29. In the restingstate of the apparatus, a clear distance remains between the connectingpart 33 and the stopper element 29 b, said clear distance being justlarge enough that the rotational block between the inner part 29 and theconnecting part 33 is released during the triggering movement of thetriggering element 28, before the stopper element 29 b terminates therelative movement of the triggering element 28 relative to theconnecting part 33 by an abutting contact.

The second blocking member 34 is tensed in the blocking engagement withthe blocking member 24 by a blocking spring 31. For this purpose, theblocking spring 31 is supported in the direction of the coupler movementX on the blocking member 34 and counter to the coupler movement X on acasing part 30 which is fixedly connected to the casing part 4. Anotherspring 32, arranged between the inner part 29 and the blocking member34, tenses the triggering element 28 relative to the blocking member 34into a proximal end position. The blocking member 34 is axially guided,such that it is secured against rotating, by the casing part 4. Thecasing part 4 forms a distal and a proximal stopper for the mobility ofthe blocking member 34.

In the resting state shown in FIG. 20, the user sets the dosage byrotating the triggering element 28 in the dosing direction. During thisrotational dosing movement, the triggering element 28 slaves theconnecting part 33 via the rotational block 29 a, 33 a, and theconnecting part 33 for its part slaves the coupler input member 6′ whichthus completes the same rotational dosing movement as the triggeringelement 28. Rotating the coupler input member 6′ tenses the drive member25. In engagement with the thread 24 b of the blocking member 24, thestopping member 27 migrates from the stopper 24 c of the thread 24 bwhich determines the zero dosage, in the direction of the stopper 24 dwhich determines the maximum dosage (FIG. 24).

The injection apparatus also offers a convenient way of correcting thedosage, as is clear from a comparison of FIGS. 20 and 22. If the userhas inadvertently set too high a dosage, he/she can correct the dosageby rotating the coupler input member 6′ back. For correcting the dosage,the user pulls the triggering element 28 in the proximal direction. Thisretracting movement of the triggering element 28 is indicated in FIG. 22by an arrow, as is the rotational direction for correcting. In theresting state of the apparatus, the inner part 29 and the blockingmember 34 are in a slaving engagement with respect to a movement in theproximal direction. The corresponding slaving elements are indicated as29 c and 34 a. The slaving element 29 c formed by the inner part 29 andthe slaving element 34 a formed by the blocking member 34 grip behindeach other and form a latch for the retracting movement of thetriggering element 28. Pulling on the triggering element 28 thus alsomoves the blocking member 34 in the proximal direction, against theforce of the blocking spring 31, thus releasing it from the blockingengagement with the blocking member 24 which abuts against the casingpart 4. As soon as the rotational block is released, the user cancorrect the dosage by means of a reverse rotational movement of thetriggering element 28 and the still extant rotationally securedengagement between the inner part 29 and the connecting part 33. As soonas the user releases the triggering element 28, it snaps back in thedistal direction together with the blocking member 34 due to the effectof the blocking spring 31, and the blocking member 34 thus snaps backinto the blocking engagement with the blocking member 24. During thereverse rotational movement, the user expediently continues to hold thetriggering element 28 fast, which is facilitated by the rotationalangular locking positions of the triggering element 28. In principle,however, the user can also let it snap back and re-dose, as applicable.

Once the desired dosage has been set, the apparatus is placed onto theskin at the desired administering location, and the injection needle isinjected. For injecting the needle, the triggering element 28 takes onanother function, for which purpose it is coupled to the needleprotection 39 (FIG. 19).

In a first phase of injecting, the user presses the injection apparatusagainst the skin, such that the needle protection 39 is moved in thedistal direction relative to the casing part 38. However, this firstpart of the movement of the needle protection 39 does not yet expose theinjection needle; rather, its tip remains short of the needle protection39. In this first phase of the injecting process, the needle protection39 abuts against a resisting element, such that it cannot be movedfurther in the distal direction relative to the casing part 38. Whilecontinuing to exert pressure on the injection apparatus in the directionof the skin, the user presses the triggering element 28 in the proximaldirection. In the course of this first phase of its triggering movement,the triggering element 28 releases an abutting contact between theneedle protection 39 and the resisting element, such that the injectionapparatus, and together with it the injection needle, are moved relativeto the needle protection 39 in the direction of the skin, and theinjection needle injects. With respect to the function of the triggeringelement 28 for injecting the needle, reference may be made to the patentapplication entitled “Attachment Module for an Injection DeviceComprising an Engagement Control for a Needle Covering Element” owned bythe owner of the present application.

As soon as the injection needle has been subcutaneously placed, thedrive member 25 can be released and the product delivered by pressingfurther onto the triggering element 28. In the second phase of thetriggering movement of the triggering element 28, which follows theinjection phase, the triggering element 28 and therefore the inner part29 is pressed further in the distal direction relative to the connectingpart 33, against the pressure of the spring 32, such that the rotationalblock (formed by components 29 a, 33 a) is released. The triggeringelement 28 can rotate idly. As soon as the rotational block has beenreleased, the stopper element 29 b passes into abutting contact with theconnecting part 33. In the third phase of the triggering movement whichthen follows, the triggering element 28 presses the connecting part 33and therefore the coupler input member 6′ via the stopper element 29 b,in the direction of the coupler movement X; in exemplary embodiments, inthe advancing direction V. Due to the effect of the spring force of theblocking spring 31, the blocking member 34 follows this movement untilit abuts against the casing part 4. Before the blocking member 34reaches the abutting position, the coupler input member 6′ passes intothe coupler engagement with the coupler intermediate member 7′. Thecoupler input member 6′ presses the coupler intermediate member 7′ outof the frictional-lock blocking engagement with the decoupling member11′, against the force of the restoring member 10′. Once the blockingengagement between the conical areas of the two members 7′ and 11′ hasbeen released and the coupler engagement therefore completelyestablished, the blocking member 34 abuts the casing part 4. In thefinal phase of the triggering movement which then follows, thetriggering element 28 presses the blocking member 24 out of the blockingengagement with the blocking member 34 via the connecting part 33.

As soon as the rotational block formed by the blocking members 24 and 34is released, the rotational drive movement of the coupler input member6′ is initiated due to the drive force of the drive member 25 and istransferred onto the coupler output member 9 via the coupler engagement.Because it is guided—such that it is secured against rotating—in thelinear guide 4 a, the piston rod 15 is moved—in the threaded engagementwith the coupler output member 9—in the advancing direction V, andproduct is delivered. This delivery movement is terminated by thestopping member 27 abutting the stopper 24 c of the blocking member 24which determines the zero dosage.

FIG. 21 shows the injection apparatus when a zero dosage or a smallpriming dosage is set, in the coupled state after the rotational blockhas been released, i.e. after the triggering element 28 has completelyperformed the triggering movement. If, advantageously, pressure iscontinuously exerted on the triggering element 28, the triggeringsequence described above progresses automatically, from injecting tocompletely delivering the dosage set.

FIG. 23 shows the injection apparatus after the container 2 has beenemptied. The casing part 1 has already been removed from the casing part4. The piston rod 15 assumes its most distal position. The decouplingmember 11′ blocks the coupler input member 6′ in the position retractedfrom the coupler intermediate member 7′. The functionality of thedecoupling member 11′ corresponds to that in the other embodiments.Unlike the two first embodiments, however, the casing part 1 and thedecoupling member 11′ are not directly in a guiding engagement with eachother, but rather via an adaptor structure 36. The adaptor structure 36is a sleeve in the casing part 4 which is fixed in and counter to thedirection of the coupler movement X in the connecting portion, but canbe rotated about the central longitudinal axis R of the casing part 4.The adaptor structure 35 forms a guiding curve 36 a either as a cavityon or a breach in its shell area facing the decoupling member 11′. Theguiding curve 35 a exhibits the course of a threaded portion. The lengthmeasured over the circumference and the pitch of the guiding curve 35 ameasured with respect to the central longitudinal axis of the casingpart 4 are dimensioned such that the decoupling member 11′ is moved intothe decoupling position shown in FIG. 21 by a quarter to a halfrevolution of the adaptor structure 35 relative to the decoupling member11′. For generating the axial movement, the decoupling member 11′engages via its engaging element 12 with the guiding curve 35 a. In thisrespect, reference is made to the statements regarding the firstembodiment.

When connecting the casing parts 1 and 4, the adaptor structure 35 formsa linear guide for the casing part 1. The casing part 1 is inserted intothe adaptor structure 35, wherein a slight frictional lock andcorrespondingly a sliding guide for the casing part 1 exists. The casingpart 1 cannot be rotated about the central longitudinal axis of thecasing part 4 relative to the adaptor structure 35. The engagement,which is rotationally secured accordingly, is established right at thebeginning of inserting the casing part 1 into the adaptor structure 35.Once the casing part 1 has been inserted until it abuts against thecasing part 4, i.e. once the coupler is accommodated at 4 a, the casingpart 1 is rotated relative to the casing part 4 and slaves the adaptorstructure 36 during this rotational movement, until the engaging element12 of the decoupling member 11′ abuts the end of the guiding curve 36 a.The rotational movement of the casing part 1 is, in some preferredembodiments, not possible until its axial abutting position, for whichpurpose a rotational block acting up until the abutting position canalso be formed between the casing parts 1 and 4.

The movement of the decoupling member 11′ caused in the guidingengagement exhibits an axial length which is greater than the length Xof the complete coupler movement. In its decoupling movement, thedecoupling member 11′ presses the coupler input member 6′ beyond itsholding position as assumed in the resting state, and blocks it in saiddecoupling position. In this forced decoupling movement, the couplerinput member 6′ slaves the triggering element 28 via the stopper element29 b. Via the latch between the slaving means 29 c and 34 a, theblocking member 34 is also slaved, against the force of the blockingspring 31, and moved out of the blocking engagement. The blocking member24 cannot follow the blocking member 34, since it is abutting againstthe casing part 4. Detaching the casing parts 1 and 4 thus releases therotational block by the decoupling mechanism which the casing parts 1and 4 form with the decoupling member 11′ via the adaptor structure 35.If the coupler input member 6′ has not yet assumed the zero dosageposition, it is rotated now at the latest into the zero dosage positionby the drive member 25, and the dosage display 20″ is zeroed. In thisrespect, reference may again be made to the particular advantage of thecoupling between the dosage display 20″ and the coupler input member 6′,namely that for each delivery, the dosage display 20″ is reset inaccordance with the delivered dosage. If, one time, the dosage set wasnot delivered, for example because the injection process was aborted orthe container 2 no longer contained the complete dosage set, the usercan read this from the dosage display 20″ which is then only partiallyreset.

Embodiments of the present invention, including preferred embodiments,have been presented for the purpose of illustration and description.They are not intended to be exhaustive or to limit the invention to theprecise forms and steps disclosed. The embodiments were chosen anddescribed to provide the best illustration of the principles of theinvention and the practical application thereof, and to enable one ofordinary skill in the art to utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the invention as determined by the appended claimswhen interpreted in accordance with the breadth they are fairly,legally, and equitably entitled.

The invention claimed is:
 1. An injection apparatus comprising: a) afirst casing part detachably coupled to a second casing part, whereinthe first casing part accommodates a container filled with a fluidproduct and the second casing part comprises a dosing and drivemechanism, the dosing and drive mechanism comprising a drive member; b)a piston accommodated in the container and adapted to be moved in anadvancing direction, wherein advancement of the piston in the advancingdirection displaces and delivers the fluid product through a needle; c)a piston rod with an outer thread and moveable in a delivery movement inthe advancing direction, wherein the drive member is for advancing thepiston rod, wherein the piston rod is linearly guided and securedagainst rotating such that the piston rod cannot be rotated relative tothe casing parts during the delivery movement; d) a coupler whichcouples the drive member to the piston rod in a coupler engagement,wherein a threaded engagement between a threaded portion of the couplerand the piston rod comprises a pitch which prevents self-locking, andwherein the coupler comprises a coupler output member in engagement withthe piston rod, and wherein a drive movement of the coupler outputmember causes the delivery movement of the piston rod; e) a drive springwhich supplies a drive force to the drive member; and f) a needleprotection structure accommodated by at least one of the first or secondcasing parts such that it can slide counter to the advancing directionagainst a force of a restoring spring.
 2. The apparatus according toclaim 1, wherein the needle protection structure is configured as asleeve.
 3. The apparatus according to claim 1, wherein the needleprotection structure is configured such that, when it slides counter tothe advancing direction, the needle penetrates through a distal openingof the needle protection structure.
 4. The apparatus according to claim1, wherein the needle protection structure is carried by a third casingpart, the third casing part coupled to at least one of the first orsecond casing parts.
 5. The apparatus according to claim 4, wherein theneedle protection structure is configured to slide counter to theadvancing direction into the third casing part.
 6. The apparatusaccording to claim 4, wherein the third casing part is configured tosnap onto the second casing part.
 7. The apparatus according to claim 4,wherein: in a first phase of injecting, the needle protection structureis moved counter to the advancing direction relative to the third casingpart such that the needle does not penetrate through a distal opening ofthe needle protection structure and the needle protection structureabuts against a resisting element that prevents its further movementcounter to the advancing direction, and upon actuating of a triggeringelement, the abutment between the needle protection structure and theresisting element is released such that the needle is moved relative tothe needle protection structure in the advancing direction.
 8. Theapparatus according to claim 1, wherein a thread pitch of a threadedengagement between a thread of the drive member and a threaded portionof the coupler is large enough that self-locking cannot occur.
 9. Theapparatus according to claim 1, wherein the piston rod extends into thedrive member and a portion of the coupler.
 10. The apparatus accordingto claim 1, wherein the thread pitch of the threaded engagement betweenthe threaded portion of the coupler and the piston rod is less than athread pitch of a threaded engagement between the drive member and thethreaded portion of the coupler.
 11. The apparatus according to claim 1,wherein the drive member is linearly guided relative to the secondcasing part such that it can be moved in and counter to the advancingdirection, for which purpose the second casing part directly forms alinear guide.
 12. The apparatus according to claim 1, wherein thecoupler comprises a sleeve-shaped coupler input member comprising athread complementary to a thread of the drive member for threadedengagement with the drive member.
 13. The apparatus according to claim1, wherein the coupler comprises a coupler intermediate member and arestoring member which charges the coupler intermediate member with anelasticity force acting counter to the advancing direction.
 14. Theapparatus according to claim 13, wherein if no force acting in theadvancing direction is exerted on the drive member the restoring memberensures, via the coupler intermediate member, the coupler engagementbetween the drive member and piston rod is released.
 15. The apparatusaccording to claim 1, further comprising a dosing member for setting adose, wherein during dose setting the dosing member is connected to aportion of the coupler such that it is secured against rotation and suchthat rotation of the dosing member causes the portion of the coupler torotate in a dosing movement.
 16. The apparatus according to claim 15,wherein the drive member is moved by the dosing movement of the portionof the coupler in a proximal direction.
 17. The apparatus according toclaim 1, wherein during the delivery movement, the drive member ispressed in the advancing direction, such that a portion of the couplerrotates in a threaded engagement with the drive member which is guidedsuch that it is secured against rotation about a common threaded axis,and wherein the portion of the coupler slaves the coupler output memberwhen rotated.